MCQ Bank

Proteins are polymers made up of amino acid monomers linked together by peptide bonds. Glucose forms carbohydrates, while disulfide bridges are structural bonds that help stabilize some proteins but are not their building blocks.

BIF401 Final Term AI Solved

Q21

Which of the following statements is true about proteins?

A) Proteins are polymers of amino acids
B) Proteins are polymers of glucose
C) Proteins are polymers of peptide bonds
D) Proteins are polymers of di-sulfide bridges

AI Explanation

MS1 measures the mass-to-charge ratio of the intact precursor molecule before fragmentation occurs. This measurement provides the molecular weight information needed for selecting ions for further analysis in MS2.

BIF401 Final Term AI Solved

Q22

The purpose of MS1 in tandem mass spectrometry (MS/MS) is …………..............

A) To fragment the intact sample molecule into two parts
B) To measure the molecular weight of the intake sample molecule
C) To match the experimental mass with theoretical peptides from a database
D) To measure the mass of the fragments produced by MS2

AI Explanation

MS1 in protein identification measures the mass-to-charge ratio of the intact precursor molecule before fragmentation. This mass information is used as an initial step in identifying and analyzing the protein.

BIF401 Final Term AI Solved

Q23

The 1-D (Primary) structure of proteins can be determined by ...............................

A) Tandem Mass Spectrometry
B) Nuclear Magnetic Resonance (NMR)
C) Both Edman Degradation & NMR
D) Edman Degradation

AI Explanation

Edman degradation is a classical technique used to determine the amino acid sequence of a protein, which defines its primary structure. Tandem mass spectrometry can also provide sequence information, but Edman degradation is the traditional method specifically associated with primary structure determination.

BIF401 Final Term AI Solved

Q24

The purpose of MS1 in protein identification ……………...........

A) To identify the fragmentation technique used
B) To measure the mass of the intact molecule in the sample
C) To determine the sequence of the protein
D) To identify the protein in the sample

AI Explanation

MS1 in protein identification measures the mass-to-charge ratio of the intact precursor molecule before fragmentation. This mass information is used as an initial step in identifying and analyzing the protein.

BIF401 Final Term AI Solved

Q25

How is the experimental mass reported from MS2 matched with theoretical peptides from a database?

A) The experimental mass is matched to the theoretical mass of the peptide with the closest match
B) The experimental mass is used to calculate the sequence of the peptide
C) Both experimental mass is compared to the theoretical masses of all the peptides in the database & experimental mass is matched to the theoretical mass of the peptide with the closest match
D) The experimental mass is compared to the theoretical masses of all the peptides in the database

AI Explanation

Quaternary structure is formed by the association of multiple polypeptide chains (subunits) that make up a functional protein. Hydrophobic interactions and other forces can contribute to protein stability, but the defining feature of quaternary structure is the arrangement of multiple peptide chains.

BIF401 Final Term AI Solved

Q26

Which of the following statements are true about quaternary structure of proteins?

A) 4’ (Quaternary) structure of proteins are formed by peptide chains that make-up the protein
B) 4’ Structures of proteins are formed as a result of hydrophobic interactions between non-polar R-groups
C) Combinations of Alpha helices, Beta sheets, coils and loops help form 3’ structures
D) Proteins comprised of only single chain have a quaternary structure

AI Explanation

Quaternary structure refers to the arrangement and interaction of multiple polypeptide chains that form a functional protein complex. The other options describe tertiary structure or incorrectly define quaternary structure.